Heat Stroke

By Jai Diggs, DVM

 

Living in southeast Louisiana has many advantages and disadvantages when it comes to running/training rabbit dogs. One of the largest disadvantages involves dealing with the heat.  I’ve had several fellow beaglers often approach me about concerns for their hounds potentially “over heating”. My goal, whenever I write an article, is to provide the information that can be used to educate my fellow houndsmen on how to keep their hounds healthy.  In this area of the Deep South, we are fortunate enough to have several beagle clubs, with most clubs hosting two licensed trials during the year – our trialing season begins in late summer. During this time of year the average temperature is 94 degrees and the humidity makes it feel much hotter.  Since the trialing season begins in late August, most houndsmen start conditioning their hounds in June or July (typically the hottest months of the year). Some of you reading this article are probably thinking, “Well, why not condition them in the early morning or late evening?” Well, during the early morning, you may only get about two hours of optimal running, if conditions permit. But, we’ll train at these hours to avoid the brutal effects of the southern heat. This article’s focus will be on heat stroke.

Heat stroke is a life threatening and potentially health-altering disease that is commonly seen in working dogs worked under extreme conditions such as: intense heat, prolonged intervals of time, or a combination of these. Because these animals are running/working, this results in a natural elevation in body temperature. The body’s temperature regulatory system helps keep dogs from overheating under normal conditions. However, when the surrounding temperature is just as hot as a dog’s normal body temperature, it makes regulation very difficult. The best way dogs attempt to cool themselves is by panting. Under the stress of extreme temperatures, this is often unsuccessful. Once the body temperature has risen and is maintained at levels far exceeding the normal range, several health concerns arise. Heat stroke is one of few diseases that can negatively affect just about every body system.

 

Heat stroke effects on the central nervous system (brain and spinal cord) can cause hounds to behave abnormally. This occurs for multiple reasons, but the prime factors are: 1) Excessive heat causes a compromise of the vascular tissue, which can lead to brain hemorrhage, 2) Hypoglycemia (low blood sugar), which is secondary to the effects that heat has on the liver. I have heard a lot of owners talk about changing foods or giving corn syrup to correct hypoglycemia, but the first and foremost correction should be to lower the dog’s body temperature. Other central nervous system problems that can be observed are: pupil dilation (early on) and pupil constriction (severe cases).  Heat stroke’s effects on the cardiovascular and respiratory system (heart and lungs) – since the dog’s internal cooling system has failed or isn’t functioning adequately – is, ultimately, a lack of oxygen circulating throughout the body. Due to the lack of oxygen, the heart beats faster than normal in an attempt to deliver oxygenated blood to vital organs and tissues. This increased heart and respiratory rate can cause cardiac and respiratory arrest. The musculoskeletal system, in severe cases, can produce a substance called myoglobin, which can be toxic to the kidneys.  Heat stroke can also, therefore, result in kidney disease. Once the animal begins to go into shock, the blood pressure begins to drop. Once this occurs, the kidneys can begin to fail. There are a multitude of other factors that can contribute to kidney failure; so given the contribution of these other factors will determine the severity of the kidney disease. When the vascular system fails, the gastrointestinal system blood supply is compromised and this causes the layer in the intestine to die, which can result in intestinal hemorrhage.  As we can see, increased body temperature plays an important role on all of the working dog’s body systems.

What are possible signs of a dog that has Heat Stroke?

-Body temperature greater than 104 degrees

-Abnormal behavior (Running fits)

-Dilated pupils

-Constricted pupils

-Panting excessively with increased upper airway noise

-Bright red gums

-Staggering when they walk

-Bloody stool

-Vomiting

-Red eyes

-Collapse

 

Prevention of Heat Stroke

The best way to prevent heat stroke is to refrain from working your hound in extreme temperatures. During trial season, I know this may be difficult, because most winners’ packs are typically held during the warmest times of the day. I recommend making sure that your hound is healthy, isn’t overweight, and is in great physical condition (this is, I find, the largest contributor to heat stroke in hunting hounds). Gradually work your dogs during the cooler parts of the day into the warmer parts of the day, always being mindful of the temperature and the length of time your hounds have been running, making sure that your dog box is well ventilated and that air flow isn’t obstructed, allowing your hounds access to water during exercise, and, if possible, cooling your hounds down with cool (not cold) water.

 

What do I do if I think my hound has heat stroke?

Cooling your dog down is the most important part of initial heat stroke management. Wet your hound down with cool water from head to tail. Once you have done this, if you have a towel, completely saturate it with cool water and wrap it around your dog’s body. Place your dog inside your vehicle, turn on the A/C at its lowest setting, and immediately head to the closest veterinary hospital. If you have someone with you while you are traveling to the veterinarian, have them fan over the dog’s head. Veterinarians used to recommend that you apply isopropyl alcohol.

 

If my dog has a heat stroke will they ever be the same?

Every case is different, but the most important component of your dog’s prognosis is how long they had been subjected to extreme heat and an elevated body temperature. The longer they had been subjected to these extreme conditions, the more likely they are to suffer permanent damage.

 

Is there a supplement that I can give my dog to help prevent heat stroke?

No supplement will prevent heat stroke, however, supplements can help your dogs restore the electrolytes and fluids that are lost during work/running in extreme heat. The most important factor in minimizing the likelihood of heat stroke is keeping your hound in excellent physical condition.

Author: dan

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